package main import ( "fmt" "os" "os/exec" "strings" "syscall" "github.com/docker/cli/cli" pluginmanager "github.com/docker/cli/cli-plugins/manager" "github.com/docker/cli/cli/command" "github.com/docker/cli/cli/command/commands" cliflags "github.com/docker/cli/cli/flags" "github.com/docker/cli/cli/version" "github.com/docker/docker/api/types/versions" "github.com/docker/docker/client" "github.com/moby/buildkit/util/appcontext" "github.com/pkg/errors" "github.com/sirupsen/logrus" "github.com/spf13/cobra" "github.com/spf13/pflag" ) func newDockerCommand(dockerCli *command.DockerCli) *cli.TopLevelCommand { var ( opts *cliflags.ClientOptions flags *pflag.FlagSet helpCmd *cobra.Command ) cmd := &cobra.Command{ Use: "docker [OPTIONS] COMMAND [ARG...]", Short: "A self-sufficient runtime for containers", SilenceUsage: true, SilenceErrors: true, TraverseChildren: true, RunE: func(cmd *cobra.Command, args []string) error { if len(args) == 0 { return command.ShowHelp(dockerCli.Err())(cmd, args) } return fmt.Errorf("docker: '%s' is not a docker command.\nSee 'docker --help'", args[0]) }, PersistentPreRunE: func(cmd *cobra.Command, args []string) error { return isSupported(cmd, dockerCli) }, Version: fmt.Sprintf("%s, build %s", version.Version, version.GitCommit), DisableFlagsInUseLine: true, CompletionOptions: cobra.CompletionOptions{ DisableDefaultCmd: false, HiddenDefaultCmd: true, DisableDescriptions: true, }, } opts, flags, helpCmd = cli.SetupRootCommand(cmd) registerCompletionFuncForGlobalFlags(dockerCli, cmd) flags.BoolP("version", "v", false, "Print version information and quit") setFlagErrorFunc(dockerCli, cmd) setupHelpCommand(dockerCli, cmd, helpCmd) setHelpFunc(dockerCli, cmd) cmd.SetOut(dockerCli.Out()) commands.AddCommands(cmd, dockerCli) cli.DisableFlagsInUseLine(cmd) setValidateArgs(dockerCli, cmd) // flags must be the top-level command flags, not cmd.Flags() return cli.NewTopLevelCommand(cmd, dockerCli, opts, flags) } func setFlagErrorFunc(dockerCli command.Cli, cmd *cobra.Command) { // When invoking `docker stack --nonsense`, we need to make sure FlagErrorFunc return appropriate // output if the feature is not supported. // As above cli.SetupRootCommand(cmd) have already setup the FlagErrorFunc, we will add a pre-check before the FlagErrorFunc // is called. flagErrorFunc := cmd.FlagErrorFunc() cmd.SetFlagErrorFunc(func(cmd *cobra.Command, err error) error { if err := pluginmanager.AddPluginCommandStubs(dockerCli, cmd.Root()); err != nil { return err } if err := isSupported(cmd, dockerCli); err != nil { return err } if err := hideUnsupportedFeatures(cmd, dockerCli); err != nil { return err } return flagErrorFunc(cmd, err) }) } func setupHelpCommand(dockerCli command.Cli, rootCmd, helpCmd *cobra.Command) { origRun := helpCmd.Run origRunE := helpCmd.RunE helpCmd.Run = nil helpCmd.RunE = func(c *cobra.Command, args []string) error { if len(args) > 0 { helpcmd, err := pluginmanager.PluginRunCommand(dockerCli, args[0], rootCmd) if err == nil { return helpcmd.Run() } if !pluginmanager.IsNotFound(err) { return errors.Errorf("unknown help topic: %v", strings.Join(args, " ")) } } if origRunE != nil { return origRunE(c, args) } origRun(c, args) return nil } } func tryRunPluginHelp(dockerCli command.Cli, ccmd *cobra.Command, cargs []string) error { root := ccmd.Root() cmd, _, err := root.Traverse(cargs) if err != nil { return err } helpcmd, err := pluginmanager.PluginRunCommand(dockerCli, cmd.Name(), root) if err != nil { return err } return helpcmd.Run() } func setHelpFunc(dockerCli command.Cli, cmd *cobra.Command) { defaultHelpFunc := cmd.HelpFunc() cmd.SetHelpFunc(func(ccmd *cobra.Command, args []string) { if pluginmanager.IsPluginCommand(ccmd) { err := tryRunPluginHelp(dockerCli, ccmd, args) if !pluginmanager.IsNotFound(err) { ccmd.Println(err) } cmd.PrintErrf("unknown help topic: %v\n", ccmd.Name()) return } if err := isSupported(ccmd, dockerCli); err != nil { ccmd.Println(err) return } if err := hideUnsupportedFeatures(ccmd, dockerCli); err != nil { ccmd.Println(err) return } defaultHelpFunc(ccmd, args) }) } func setValidateArgs(dockerCli command.Cli, cmd *cobra.Command) { // The Args is handled by ValidateArgs in cobra, which does not allows a pre-hook. // As a result, here we replace the existing Args validation func to a wrapper, // where the wrapper will check to see if the feature is supported or not. // The Args validation error will only be returned if the feature is supported. cli.VisitAll(cmd, func(ccmd *cobra.Command) { // if there is no tags for a command or any of its parent, // there is no need to wrap the Args validation. if !hasTags(ccmd) { return } if ccmd.Args == nil { return } cmdArgs := ccmd.Args ccmd.Args = func(cmd *cobra.Command, args []string) error { if err := isSupported(cmd, dockerCli); err != nil { return err } return cmdArgs(cmd, args) } }) } func tryPluginRun(dockerCli command.Cli, cmd *cobra.Command, subcommand string, envs []string) error { plugincmd, err := pluginmanager.PluginRunCommand(dockerCli, subcommand, cmd) if err != nil { return err } plugincmd.Env = append(envs, plugincmd.Env...) go func() { // override SIGTERM handler so we let the plugin shut down first <-appcontext.Context().Done() }() if err := plugincmd.Run(); err != nil { statusCode := 1 exitErr, ok := err.(*exec.ExitError) if !ok { return err } if ws, ok := exitErr.Sys().(syscall.WaitStatus); ok { statusCode = ws.ExitStatus() } return cli.StatusError{ StatusCode: statusCode, } } return nil } func runDocker(dockerCli *command.DockerCli) error { tcmd := newDockerCommand(dockerCli) cmd, args, err := tcmd.HandleGlobalFlags() if err != nil { return err } if err := tcmd.Initialize(); err != nil { return err } var envs []string args, os.Args, envs, err = processAliases(dockerCli, cmd, args, os.Args) if err != nil { return err } err = pluginmanager.AddPluginCommandStubs(dockerCli, cmd) if err != nil { return err } if len(args) > 0 { ccmd, _, err := cmd.Find(args) if err != nil || pluginmanager.IsPluginCommand(ccmd) { err := tryPluginRun(dockerCli, cmd, args[0], envs) if !pluginmanager.IsNotFound(err) { return err } // For plugin not found we fall through to // cmd.Execute() which deals with reporting // "command not found" in a consistent way. } } // We've parsed global args already, so reset args to those // which remain. cmd.SetArgs(args) return cmd.Execute() } func main() { dockerCli, err := command.NewDockerCli() if err != nil { fmt.Fprintln(os.Stderr, err) os.Exit(1) } logrus.SetOutput(dockerCli.Err()) if err := runDocker(dockerCli); err != nil { if sterr, ok := err.(cli.StatusError); ok { if sterr.Status != "" { fmt.Fprintln(dockerCli.Err(), sterr.Status) } // StatusError should only be used for errors, and all errors should // have a non-zero exit status, so never exit with 0 if sterr.StatusCode == 0 { os.Exit(1) } os.Exit(sterr.StatusCode) } fmt.Fprintln(dockerCli.Err(), err) os.Exit(1) } } type versionDetails interface { Client() client.APIClient ServerInfo() command.ServerInfo } func hideFlagIf(f *pflag.Flag, condition func(string) bool, annotation string) { if f.Hidden { return } var val string if values, ok := f.Annotations[annotation]; ok { if len(values) > 0 { val = values[0] } if condition(val) { f.Hidden = true } } } func hideSubcommandIf(subcmd *cobra.Command, condition func(string) bool, annotation string) { if subcmd.Hidden { return } if v, ok := subcmd.Annotations[annotation]; ok { if condition(v) { subcmd.Hidden = true } } } func hideUnsupportedFeatures(cmd *cobra.Command, details versionDetails) error { var ( notExperimental = func(_ string) bool { return !details.ServerInfo().HasExperimental } notOSType = func(v string) bool { return v != details.ServerInfo().OSType } notSwarmStatus = func(v string) bool { s := details.ServerInfo().SwarmStatus if s == nil { // engine did not return swarm status header return false } switch v { case "manager": // requires the node to be a manager return !s.ControlAvailable case "active": // requires swarm to be active on the node (e.g. for swarm leave) // only hide the command if we're sure the node is "inactive" // for any other status, assume the "leave" command can still // be used. return s.NodeState == "inactive" case "": // some swarm commands, such as "swarm init" and "swarm join" // are swarm-related, but do not require swarm to be active return false default: // ignore any other value for the "swarm" annotation return false } } versionOlderThan = func(v string) bool { return versions.LessThan(details.Client().ClientVersion(), v) } ) cmd.Flags().VisitAll(func(f *pflag.Flag) { // hide flags not supported by the server // root command shows all top-level flags if cmd.Parent() != nil { if cmds, ok := f.Annotations["top-level"]; ok { f.Hidden = !findCommand(cmd, cmds) } if f.Hidden { return } } hideFlagIf(f, notExperimental, "experimental") hideFlagIf(f, notOSType, "ostype") hideFlagIf(f, notSwarmStatus, "swarm") hideFlagIf(f, versionOlderThan, "version") }) for _, subcmd := range cmd.Commands() { hideSubcommandIf(subcmd, notExperimental, "experimental") hideSubcommandIf(subcmd, notOSType, "ostype") hideSubcommandIf(subcmd, notSwarmStatus, "swarm") hideSubcommandIf(subcmd, versionOlderThan, "version") } return nil } // Checks if a command or one of its ancestors is in the list func findCommand(cmd *cobra.Command, commands []string) bool { if cmd == nil { return false } for _, c := range commands { if c == cmd.Name() { return true } } return findCommand(cmd.Parent(), commands) } func isSupported(cmd *cobra.Command, details versionDetails) error { if err := areSubcommandsSupported(cmd, details); err != nil { return err } return areFlagsSupported(cmd, details) } func areFlagsSupported(cmd *cobra.Command, details versionDetails) error { errs := []string{} cmd.Flags().VisitAll(func(f *pflag.Flag) { if !f.Changed { return } if !isVersionSupported(f, details.Client().ClientVersion()) { errs = append(errs, fmt.Sprintf(`"--%s" requires API version %s, but the Docker daemon API version is %s`, f.Name, getFlagAnnotation(f, "version"), details.Client().ClientVersion())) return } if !isOSTypeSupported(f, details.ServerInfo().OSType) { errs = append(errs, fmt.Sprintf( `"--%s" is only supported on a Docker daemon running on %s, but the Docker daemon is running on %s`, f.Name, getFlagAnnotation(f, "ostype"), details.ServerInfo().OSType), ) return } if _, ok := f.Annotations["experimental"]; ok && !details.ServerInfo().HasExperimental { errs = append(errs, fmt.Sprintf(`"--%s" is only supported on a Docker daemon with experimental features enabled`, f.Name)) } // buildkit-specific flags are noop when buildkit is not enabled, so we do not add an error in that case }) if len(errs) > 0 { return errors.New(strings.Join(errs, "\n")) } return nil } // Check recursively so that, e.g., `docker stack ls` returns the same output as `docker stack` func areSubcommandsSupported(cmd *cobra.Command, details versionDetails) error { // Check recursively so that, e.g., `docker stack ls` returns the same output as `docker stack` for curr := cmd; curr != nil; curr = curr.Parent() { if cmdVersion, ok := curr.Annotations["version"]; ok && versions.LessThan(details.Client().ClientVersion(), cmdVersion) { return fmt.Errorf("%s requires API version %s, but the Docker daemon API version is %s", cmd.CommandPath(), cmdVersion, details.Client().ClientVersion()) } if os, ok := curr.Annotations["ostype"]; ok && os != details.ServerInfo().OSType { return fmt.Errorf("%s is only supported on a Docker daemon running on %s, but the Docker daemon is running on %s", cmd.CommandPath(), os, details.ServerInfo().OSType) } if _, ok := curr.Annotations["experimental"]; ok && !details.ServerInfo().HasExperimental { return fmt.Errorf("%s is only supported on a Docker daemon with experimental features enabled", cmd.CommandPath()) } } return nil } func getFlagAnnotation(f *pflag.Flag, annotation string) string { if value, ok := f.Annotations[annotation]; ok && len(value) == 1 { return value[0] } return "" } func isVersionSupported(f *pflag.Flag, clientVersion string) bool { if v := getFlagAnnotation(f, "version"); v != "" { return versions.GreaterThanOrEqualTo(clientVersion, v) } return true } func isOSTypeSupported(f *pflag.Flag, osType string) bool { if v := getFlagAnnotation(f, "ostype"); v != "" && osType != "" { return osType == v } return true } // hasTags return true if any of the command's parents has tags func hasTags(cmd *cobra.Command) bool { for curr := cmd; curr != nil; curr = curr.Parent() { if len(curr.Annotations) > 0 { return true } } return false }